Microscope drapes are commonly used in surgical procedures to completely house an unsterile microscope and its support arm in a manner to substantially preclude the exhaust of heated air into an operating room at a location adjacent to the operating zone and/or the patient being operated upon. The sterile covering will also prevent the surgeon's hands from coming into contact with the non-sterile microscope.
Various means of securing the drape to the oculars of a microscope have been used. In general, the ocular housing portions of the drape are pulled downwardly over and then securely though releasably fastened to oculars as described in U.S. Pat. No. 3,698,791 by the use of pressure sensitive adhesive and very commonly by the use of rubber bands.
Pressure sensitive adhesive transfer tape with a removable top liner which covers the tape prior to application of the drape may be attached adjacent to the opening for the oculars. The liner is removed and the exposed adhesive used to effect a closure. This type of closure is frequently a one chance operation because if the closure is not adequate and insufficient adhesive is left to adjust the closure, the closure cannot be made more secure. Another problem is present with this type of means for closure. If the liner is inadvertently removed during drape installation or extreme care is not taken in handling the drape after the liner is removed, the adhesive may contact and stick to the drape body and any attempt to separate the drape body from the adhesive will likely result in a torn drape or the drape may stick to the surgical gloves of the nurse installing the drape.
As mentioned above, rubber bands may be used to effect a closure. They are commonly attached to the drape by the drape manufacturer with masking tape when the drape is packaged. To secure the drape to the oculars, the rubber bands must first be removed from the attachment point and then slipped over the oculars. This requires manual skill and is time consuming. Additionally, if a rubber band breaks or is dropped, sterile replacements are required which may not be readily available.
Interference fit ocular housings have been used; however, they require intense concentration and dexterity to install over the oculars. The aperture of the housing must be precisely sized to each particular type of ocular and torn seams frequently result from stress during installation.
It is apparent from the foregoing that none of the above-described methods of securing the ocular housings of microscope drapes to the oculars is entirely satisfactory.